1. Related Applications
This invention is related to our co-pending application Ser. No. 222,700, filed July 22, 1988, on the same date as this application and entitled A HIGH SPEED MULTI-CHANNEL PHASE DETECTOR.
2. Field of the Invention
The present invention is related to lock detectors for high speed phase locked loops of the type employed in quadrature phase shift key (QPSK) receivers. More particularly, the present invention relates to a high speed and high frequency function generators and analog multipliers which eliminate the need for low frequency analog multipliers and frequency squaring multipliers which limit the useful frequency of a lock detector.